ABSTRACT
Objective@#To explore the blood lead level and its relationship with behavior in school-age children from rural areas of Chongqing.@*Methods@#A total of 697 students from grades 3 to 6 in the fall semester of 2014 from 14 rural townships in one district of Chongqing was selected by using the random cluster sampling method. Blood were sampled to analyze the lead level. Neurobehavioral tests were performed to determine their personal cognitive and memory ability. Questionnaires and physical examinations were administered to obtain the information of confounding factors. All students were divided into Q1-Q4 groups according to the quartile of their blood lead level. The relationship between the blood lead level and behavior was analyzed by multivariate logistic regression model and restricted spline regression model.@*Results@#The mean age of 697 students was (10.07±1.36) years old, and the median (interquartile range) of their blood lead level was 44.31 (35.42) μg/L. Multivariate logistic regression model showed that after adjusting for age, gender, body mass index and maternal culture level, compared with Q1 group, the OR (95%CI) values of high digit symbol substitution test (DSST) scores and high overall memory quotient (MQ) scores in Q3 group were 1.65 (1.01-2.70) and 2.10 (1.21-3.62), and the OR (95%CI) value of high long term memory (LTM) scores in Q4 group was 0.53 (0.31-0.92). The results of the restricted spline regression model showed that the dose-response curves between the blood lead level and MQ/LTM test scores were both parabolic (P<0.05).@*Conclusion@#The blood lead level of school-age children from rural areas of Chongqing is the same as that from other areas of China, but slightly higher than that from other areas of Chongqing. Children with higher blood lead level have poor long-term memory ability.
ABSTRACT
Previous reports indicated that XRCC1 Arg280His polymorphism might be a possible risk factor for several cancers. Published studies on the association of XRCC1 Arg280His polymorphisms with glioma risk have yielded controversial results. The present study aimed to derive a more precise estimation of the relationship. Meta-analyses assessing the association of XRCC1 Arg280His variation with glioma were conducted and subgroup analyses on ethnicity and source of controls were further performed. Eligible studies for the period up to May 2012 were identified. A total of four case-control studies comprising 1439 cases and 2564 controls were selected for analysis. The overall data indicated no significant association of XRCC1 Arg280His polymorphism with glioma risk [His vs Arg: OR=1.05; 95%CI=0.88-1.25; His/His vs Arg/Arg: OR=1.42; 95%CI=0.87-2.29; dominant model: OR=1.00; 95%CI=0.82-1.22; recessive model: OR=1.41; 95%CI=0.88-2.25]. Likewise, in the subgroup analysis regarding ethnicity and source of controls, no associations were observed. The results of the present study failed to suggest an association of XRCC1 Arg 280 Hispolymorphism with glioma risk. Further large and well-designed studies are needed to confirm this conclusion
Subject(s)
DNA-Binding Proteins , Polymorphism, GeneticABSTRACT
P21 (CDKN1A), a key cell cycle regulatory protein that governs cell cycle progression from G1 to S phase, can regulate cell proliferation, growth arrest, and apoptosis. The Ser31Arg polymorphism is located in the highly conserved region of p21 and may encode functionally distinct proteins. Although many epidemiological studies have been conducted to evaluate the association between the p21 Ser31Arg polymorphism and cancer risk, the findings remain conflicting. This meta-analysis with 33 077 cases and 45 013 controls from 44 published case-control studies showed that the variant homozygous 31Arg/Arg genotype was associated with an increased risk of numerous types of cancers in a random-effect model (homozygote comparison: OR = 1.17, 95% CI = 0.99 to 1.37, P = 0.0002 for the heterogeneity test; recessive model comparison: OR = 1.16, 95% CI = 1.01 to 1.33, P = 0.0001 for the heterogeneity test). Stratified analysis revealed that increased cancer risk associated with the 31Arg/Arg genotype remained significant in subgroups of colorectal cancer, estrogen-related cancer, Caucasians, population-based studies, studies with matching information or a larger sample size. Heterogeneity analysis showed that tumor type contributed to substantial between-study heterogeneity (recessive model comparison: Χ(2) = 21.83, df = 7, P = 0.003). The results from this large-sample sized meta-analysis suggest that the p21 31Arg/Arg genotype may serve as a potential marker for increased cancer risk.
Subject(s)
Humans , Asian People , Genetics , Breast Neoplasms , Genetics , Case-Control Studies , Colorectal Neoplasms , Genetics , Cyclin-Dependent Kinase Inhibitor p21 , Genetics , White People , Genetics , Gene Frequency , Genetic Heterogeneity , Genotype , Lung Neoplasms , Genetics , Odds Ratio , Polymorphism, Genetic , Risk FactorsABSTRACT
Objective To construct the small interfering RNA (siRNA) eukaryotic expression vector specific to human MGMT gene(pRNATin-H1.2/Neo MGMT siRNA) to observe its silencing effect on MGMT gene in vitro.Methods The pRNATin-H1.2/Neo MGMT siRNA expression vector was constructed by gene recombination,then transfected into the cultured HelaS3 cells.Inhibitory effect of siRNAs was detected by semi-quantitative RT-PCR.Results The pRNATin-H1.2/Neo MGMT siRNA expression vector was successfully constructed.Cells transfected with pRNATin-H1.2/Neo MGMT siRNA could obviously inhibit the expression level of MGMT gene.Conclusion The pRNATin-H1.2/Neo MGMT siRNA expression vector could inhibit the MGMT gene expression.